Category:Point Spectra (Densely-Defined Linear Operators)

This category contains results about point spectrums in the context of Densely-Defined Linear Operators.
Definitions specific to this category can be found in Definitions/Point Spectra (Densely-Defined Linear Operators).

Let $\struct {\HH, \innerprod \cdot \cdot}$ be a Hilbert space over $\C$.

Let $\struct {\map D T, T}$ be a densely-defined linear operator.

We define the point spectrum $\map {\sigma_p} T$ as the set of $\lambda \in \C$ such that:

$T - \lambda I$ is not injective.